Truck bumper shell and method of retrofit installation

ABSTRACT

A method uses retrofitably-attachable pre-formed shell to cover exposed areas of existing stamped/formed chrome or painted truck bumpers, providing a unique re-useable decorative/protective plastic shell cover, the edges of which are tucked under the existing trim pieces of the bumper as a main attachment mechanism. The formed shells can be used to cover existing minor damage on the bumper. Light-passing images can be incorporated on the bumper shells, and backlit without changes to the bumper or deviation from the original surface profile of the bumper. Methods of forming the shells include vacuum forming, and include forming a raised perimeter guide, allowing the molded parts to be trimmed using a rotary cutting tool that follows the perimeter guide, thus reducing capital investment and tooling costs.

This application is a divisional of U.S. patent application Ser. No.14/336,319, filed on Jul. 21, 2014, entitled TRUCK BUMPER SHELL ANDMETHOD OF RETROFIT INSTALLATION, issued as U.S. Pat. No. 9,487,170,which claims the benefit of U.S. Provisional Application Ser. No.61/856,882, filed Jul. 22, 2013, entitled TRUCK BUMPER SKIN SYSTEM ANDMETHOD OF REPAIR, the entire contents of which are incorporated hereinin their entirety.

BACKGROUND OF THE INVENTION

The present invention relates to pre-formed thin-walled members, orbumper shells, used to cover vehicle bumpers (such as truck bumpers)having new or damaged show surfaces, and more particularly relates to abumper covering system that adds value in terms of appearance,customizability, novelty and curb appeal; protects the bumper from minordamage, reduces repair expense, improves ease of repair; and thatprovides optional new lighting and visual effects.

Bumpers used on most body-on-chassis trucks have traditionally beenstamped steel, either chromed or painted, serving bothdecorative/styling and impact protection functions. The manufacturingprocess of stamping steel and the fact the stamping needs to provide animpact function places many styling restraints on these types ofbumpers. Additional molded plastic trim pieces that cover portions ofthe stamping are used to provide some styling differentiation orfunction, such as a step pad. These trim pieces are usuallymolded-in-color black and textured and attached to the bumper withintegrated snap fits and clips (see FIG. 1).

Improvements are desired for several reasons. For example, bumpersquickly become worn or damaged, yet it is excessively expensive orimpossible to have them repaired, such that truck owners do not get themrepaired. This happens despite the fact that many truck owners are veryproud of their trucks and want the truck to be a show piece (even afterheavy use). Still further, many truck owners want to be able tocustomize their trucks, both to make the truck unique and customized totheir personality, but also often to “make a statement” with theirtruck. However, existing bumper covering systems are generally eithertoo expensive to allow the truck owner to make the truck unique, and/ordo not cover existing damage. For example, full fascia systems requireexpensive tooling, resulting in high cost of amortization and subsequentpainting. Although chrome bumpers cannot be repaired to their originalstate, small dents/dings can be pounded out, ground down, and the bumperpainted. However, this repair is very time consuming and costly and thepaint is easily scratched off, with the underlying chrome showingthrough. Bumpers can also be vinyl wrapped. However, the thin vinylconforms to the surface of the bumper, thus any existing damage wouldread through to the outer surface. The reader's attention is directed tothe discussion of prior art bumpers illustrated in FIGS. 1-4 below.

SUMMARY OF THE INVENTION

In one aspect of the present invention, a method of repair comprisesattaching a pre-formed polymeric shell to a formed vehicle bumper beamto cover a show surface of the vehicle bumper beam, the pre-formedpolymeric shell having a non-planar three-dimensional internal surfacethat generally matches an original undamaged shape of the show surfaceand having sufficient rigidity to maintain a shape of the polymericshell without full contact against the show surface of the formedvehicle bumper beam.

In another aspect of the present invention, a method of trimming a shellcomponent comprises using a vacuum-forming tool to form a vacuum-moldedcomponent that includes a shell and a raised tool guide extending arounda perimeter of the shell, the raised tool guide being at a specificdistance from a desired trim edge of the shell; and cutting the shellfrom the component using a cutting tool that slideably engages theraised tool guide as the cutting tool is moved around the shell.

In another aspect of the present invention, a method of customizing abumper on a vehicle comprises providing a vehicle bumper beam with aconvex outer surface; vacuum-forming a molded component from a sheet ofconstant thickness material to form a shell having walls of similarthickness but with some stretched wall thicknesses and having a shapedinner surface matching a portion of the convex outer surface;aesthetically treating an outer surface of the shell to form anaesthetic outer surface; and attaching the molded component to thevehicle bumper beam with the aesthetic outer surface covering ajuxtaposed mating portion of the convex outer surface of the vehiclebumper beam, to thus give the vehicle a new customized bumperappearance.

In another aspect of the present invention, a method of repair comprisesforming a sheet of constant thickness into a three-dimensionallyconcavely-shaped shell with inner surface replicating a mating showsurface of a vehicle component and with an outer surface aestheticallytreated to provide a customized appearance different than the matingshow surface of the vehicle component; and attaching the shell to thevehicle component to thus cover the mating show surface of the vehiclecomponent.

These and other aspects, objects, and features of the present inventionwill be understood and appreciated by those skilled in the art uponstudying the following specification, claims, and appended drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1-4 are perspective views illustrating various prior art bumpersystems discussed below.

FIG. 5 is a perspective view of a shell for covering an end of a bumperbeam, the shell embodying the present invention.

FIGS. 6A-6D are two perspective views and two cross-sectional viewsshowing installation of the shell in FIG. 5 to a truck bumper beam in abumper system, FIGS. 6C and 6D showing alternative integral attachmentflange configurations.

FIG. 6E is a perspective view of a complete bumper beam and bumpersystem, with the present shell including first and second end shells anda center shell, each including edge-located integral attachment flangesand inboard tab inter-fit with each other and with the existing bumpersystem for secure retrofit attachment.

FIG. 7 is a perspective view of a modified shell (also called a “shellcomponent”) similar to FIG. 6B but modified to have a different outersurface profile.

FIGS. 8A-8B are perspective views of an as-formed vacuum-moldedcomponent that includes the end shell of FIG. 5 and that includes araised ridge forming a guide for a cutting tool, such as a router shownin FIG. 8B.

FIG. 8C is a side view of the router in FIG. 8B, and FIGS. 8D and 8E aretop and side schematic views showing engagement of a router guide withthe guiding ridge on the vacuum-molded component of FIGS. 8A-8B and alsoshowing a relative position of the router's cutter.

FIGS. 9A-9D are shell coverings like that shown in FIG. 5, but withdifferent surface treatments, and FIG. 9E is a cross section throughFIG. 9A showing different layers including a soft/tacky layer ofpolyurethane for energy absorption and adhesion to underlying metalbumper surface being covered.

FIG. 10 is a perspective view of an existing truck bumper system inprior art.

FIGS. 11, 12A-12E and 13 are views of modified innovative shellcoverings installed over the end of the bumper system in FIG. 10, eachhaving a different light-passing portion therein, FIG. 11 showing alight-passing portion in the form of letters, FIGS. 12A-12B showing anunlit and lighted version of a light-passing portion with the windowforming a duck head, FIG. 12C showing a vertical cross section throughFIG. 12B including an electro luminescent (EL) film generating light forshining through the window, FIG. 12D showing a light-passing portionforming a trademarked brand or symbol, FIG. 12E showing a vertical crosssection through FIG. 12D including showing a colored outer panel placedacross the window on the shell, and FIG. 13 showing a grille-likelight-passing portion forming a rear bumper light (or back-up light).

FIGS. 14A-14B are perspective views of a bumper beam in prior art bumpersystem, where the beam has a rusted out spot (FIG. 14A) and a damageddented spot (FIG. 14B).

FIG. 15 is a perspective view of a shell of the present innovationinstalled on the beam of FIGS. 14A-14B.

DESCRIPTION OF PRIOR ART

FIG. 1 illustrates a bumper system 25 in prior art where its stampedbumper beam (illustrated as beam 30) is limited to simple shapes. Theexposed steel of the beam 30 is directly exposed to damage from impacts(minor and major), such as rock impingement, scratches, or low speedimpacts/bumps/scuffs, as well as environmental damage such as corrosion.Because the mild steel used in stamping bumpers can be relatively easilyformed in to a permanent shape, these minor impacts can lead topermanent dents and dings that cannot be easily repaired, thus requiringexpensive full replacement. Attached to the illustrated beam 30 are“bumper-covering accessories” (also called “existing trim” herein), suchas top end tread pieces 31 and 32 and center tread piece 33, and othercomponents such as license plate light 34. Each of the illustrated trim31-33 only cover a portion of the beam 30, and in particular include ahorizontal section covering an associated top surface of the beam 30,and include downwardly-extending outer flanges 31A-33A, respectively,covering an upper horizontal edge of a vertical portion of the beam 30.The trim 31-33 (and other bumper covering components) are attached bymany different means, such as mechanically and/or adheringly. As usedherein, the term “trim” (and “tread pieces”) is not intended to beunnecessarily limiting, and instead are intended to be interpreted asincluding various bumper covering components attached to a bumper beamto cover selected areas of the beam for aesthetics and/or function.

The bumper system 25 is intended to illustrate a variety of existingprior art bumper systems, and it will be apparent to persons skilled inthis art that the present innovation is not believed to be limited toonly being used with the specifically illustrated bumper system nor thespecifically illustrated bumper components shown. For example, FIGS. 2-4show various truck rear ends incorporating a bumper system (25) notunlike that shown in FIG. 1. The investigation shows that the edges31A-33A and also the edges 31B-33B usually have (or often have) anunfastened edge or free/unattached outer edge portion. Sometimes,stickers or adheringly attached thin-sheet coverings 35 (FIG. 4) areused on exposed portions of the beam 30. Persons skilled in the art ofvehicle bumper systems will understand that the bumper system 25 issufficient to exemplify a large number of such existing bumper systems,and that the present concept is not limited to only being used with thespecific illustrated bumper system 25.

Because of the high cost of tooling the stamped bumpers, OEMs (originalequipment manufacturers, such as automotive companies that assemble andsell vehicles) do “styling refreshments” as a truck model ages.Sometimes, the styling refreshments are done because consumers aregiving the vehicles poor marks. However, the styling refreshments do notusually include the bumpers, because of high cost. In addition, the factthat the bumper shape/style is directly linked to the impact andstructural integrity of the bumper system is also a deterrent toproviding many options or model “freshening” due to the additionalengineering and validation costs. Specifically, any structural change toa bumper system may require validation testing, which is expensive, timeconsuming, and a significant event that adds time delays and high costto bringing new/refreshed models to market.

In contrast, it is noted that the bumpers used on most uni-bodypassenger vehicles are typically constructed of a very stiff and strongtubular reinforcement or impact bar made from UHSS or Aluminum. Aplastic or foam isolator or energy absorber is typically used on theface of the impact bar to absorb low speed impacts and prevent permanentdamage. These bumper systems are completely covered by a mostlydecorative fascia or cover molded from a flexible/elastomeric material,such as TPO (thermoplastic olefin) or RRIM (reinforced reactioninjection molded part) so as to be resilient to low speed impacts. Thesedecorative fascias can be sculpted by designers independent of theimpact bar shape to enhance the styling and aerodynamics of the vehicleand have negligible influence on impact performance. Therefore, when itcomes time to refresh or differentiate the look of the vehicle, thesefascias are usually one of the first things changed . . . because of thesignificant effect on the style of the vehicle, the relatively low costof re-tooling, and the minimal re-engineering or validation (since thebumper beam under the fascia can remain the same).

Current options available to truck owners that would like torestyle/customize the look of their truck bumper and/or add protectionare usually either by: 1) Replacing the entire bumper with anaftermarket bumper (see FIG. 2—showing a typical aftermarket rear truckbumper), or 2) Covering the entire bumper with a large molded plasticfascia that would typically require additional painting at a body shop(see FIG. 3—showing a typical aftermarket rear truck bumper cover), or3) Through applying a decorative film (car wrap) directly on to thesurface of the steel bumper (see FIG. 4—showing a truck bumper withdirectly applied decorative film). Each of these alternatives hascertain limitations that the current invention is designed to overcome.For instance, replacing the current OEM bumper with an aftermarketbumper is expensive and may not meet the same functional performance ofthe OEM bumper. The aftermarket molded fascias are also expensive,especially with the addition of paint costs, are typically not verydurable, and may not fit well. The decorative films cannot change thegeometric styling of the bumper, do not add significant protection forthe bumper or cover existing damage, and cannot be taken off andre-used. They are also difficult to install, thus typically requiring aprofessional installer at additional expense. Thus, known bumpercovering systems do not satisfy several known limitations and/orproblems associated with existing bumpers, nor worn/damaged bumpers asnoted above.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

A bumper shell 50 (also sometimes called a “skin” or “shell covering” or“shell component” herein) is a molded plastic piece of semi-rigidresilient-but-stiff component designed to form fit over (or “gloveonto”) the exposed outer steel surface of a truck bumper. The shells 50at right and left ends of the bumper are mirror images of each other,such that a description of shells 50 in FIGS. 5-6B, 7, 9A-9D, 11,12A-12B, 12D, 13 and 15 are sufficient for an understanding by personsskilled in this art. The illustrated shell 50 is typically 1.5 to 3 mmthick (or more preferably about 2 mm thick), and molded from atransparent material such as PET-G, Acrylic, or Polycarbonate (see FIG.5). It can be any shape or style needed to cover a bumper beam, in termsof height, length, L-shape, and concavity, and may have (as many)attachment tabs or edge flanges as needed. The shell 50 can be made froman opaque material if a light-passing section is not required andvolumes are sufficient to support the use of different materials, asdiscussed below.

The illustrated shell 50 is a vacuum-formed thin-walled form-fitdecorative component, referred to as a “shell” herein due to isself-supporting resilient-but-relatively-rigid shape. The shell 50includes a front vertical wall portion 51, a wrapped-end portion 52, anda reversely-formed lower flange 53 extending under portions 51-52. Itsupper edge 54 and inboard edge 55 include outwardly-extendingintegrally-formed attachment flanges 56 and/or long attachment tabs 57shaped to tuck under the free edges 31A-33A, 31B-33B discussed above(FIG. 1). The flanges 56/tabs 57 preferably are positioned on enoughedges of the shell 50 to secure the shell 50 to a beam 30. It is notedthat the wrapped-end portion 52 and/or the lower flange 53 may beadditionally attached via double sided tape or clips.

The shell 50 has a concavely-shaped inner surface 58 that mateablyengages and generally matches a curved show surface of the associatedexisting bumper beam (30). It is noted that vacuum-forming processes andtooling are particularly adapted to manufacture shells 50 patternedafter the existing bumper beam 30 at low cost, even with low volumeproduction runs. The shell 50 further includes an aesthetically treatedouter surface 59 that aesthetically covers the underlying curved showsurface of the beam 30. The attachments 56-57 are adapted to attach theshell 50 to the existing vehicle bumper beam 30 via the flanges 56/tabs57 tucking under the free edge of the existing trim accessories 31-33.As noted above, additional attachments can be used if necessary tosecurely hold the shell(s) 50 on the beam (30), such as mechanical oradhesion based attachments.

FIG. 5 illustrates one such molded plastic transparent bumper shell.However, as noted above, other thicknesses and materials can be used.Nonetheless, it is noted that thin parts such as these bumper shellswith large projected surface area are difficult to mold via injectionmolding, and further it is noted that injection molding requiresexpensive tooling. For that reason, vacuum forming is the preferredmethod for forming these thin shells (including the shell in FIG. 5),especially when considering there may be multiple different models andsome lower volume runs. Nevertheless, it is contemplated that a scope ofthe present innovation includes various molding technologies (includinginjection molding, transfer molding, and compression molding) as aforming option, particularly when volumes are high enough to justify thecost of capital. It is noted that non-clear materials can be used tomanufacture shells when no backlighting is applied.

Rather than one large piece that covers the entire bumper like currentaftermarket fascia products, which also would require very large toolsand molding presses, the present bumper shell innovation includescombining multiple shells 50, 50C to cover a bumper beam (see FIG. 6E)by preferably dividing the task into two or more pieces, and furtherthey only cover the exposed metal portions of bumpers (and do not coverthe existing plastic trim). Specifically, FIG. 6E illustrates athree-piece shell covering including beam-end-covering shells 50 andcenter shell 50C. The center shell 50C is not unlike shells 50 (FIG. 5)but instead includes flanges and tabs shaped to engage the free edge ofthe center bumper step under the license plate area, and to engageadjacent edges of the end-covering shells 50. By splitting the systeminto 3 shells 50 and 50C, this helps keep tooling cost down, which isvery important for aftermarket products. In addition, it helps maintainthe functions of the existing plastic trim and some continuity of stylewith the rest of the truck. It also allows for more precise gap/fitadjustments to match the surrounding truck features than other one piecesolutions (aftermarket bumpers and fascia).

Multi-piece shell coverings of the present invention provide additionaladvantages. By being separated into separate pieces, the material isalso allowed to move during expansion and contraction due to temperaturechanges without distortion (which can be a problem on current fulllength fascia alternatives). Also, the multi-piece designs present a“natural aesthetic” for many truck bumper designs, because the OEM's(original equipment manufacturer's) style applies a plastic trim throughthe middle of the bumper, making a natural left and right half. Notably,some existing bumpers have a chromed or painted steel bumper beam thatis continuous from left to right, so there is no natural break. (SeeFIG. 2.) However, in these cases, a left and right bumper shell can beformed with a third piece/shell bridging between the two. (See FIG. 6E.)This third piece (i.e. the center shell) can either have the same look(texture/pattern/color) as the left and right shells, or it can beintentionally made different, such as a black intermediate shell/trimpiece, depending on the desired style. This middle piece would normallybe in the towing area, which is normally the most susceptible area fordamage to the bumper, such as from hitching a trailer. Therefore, thisthird/middle piece can be constructed of a thicker and moreelastomeric/impact resistant material, such as TPO, to minimize damageto the bumper. It may also be replaced independently, if damaged. Theintersecting edges of the center piece and the side pieces are offset toreduce the visibility of the joint as shown below, with the center piecealways on top to retain the side pieces against the bumper. The centerpiece is typically attached to the bumper with magnetic or double-sidedtape. Since many truck bumpers are damaged in the center/hitch mountarea from towing incidents. The center cover section may also be appliedas a “stand alone” piece, i.e. without the side pieces, as an individualcover for the damaged center section of truck bumpers.

Intersection joint design between a bumper shell and existing trim: Aunique feature of the present bumper shell 50 (and 50C) is the offsetperimeter flanges 56 and tabs 57, (like those shown in FIGS. 5 and6A-6D), which are formed in the bumper shell so they can be tucked underthe existing plastic trim pieces of the bumper and thereby provide themain attachment function and to completely hide most edges, creating avery high quality look. Since the shell components have significantstructural strength, the perimeter flanges and any attachment tabsextending therefrom are sufficient to securely retain the present bumpershell components in place.

FIG. 6 illustrates a bumper shell 50 installed with flanges/tabs 56/57tucked under existing plastic trim. By keeping the shell thin (such asless than 3 mm), it is relatively easy to tuck the flanges between thebumper and the existing trim pieces with minimal distortion of the trimand minimal effect on the re-installation effort of the trim piece. Anyremaining free edges (such as along a lower edge or outer vertical edgeon the wrapped portion) can be attached with re-useable methods, such asmagnetic tape or clips, if necessary. For more permanent installation,other means, such as double sided tape may also be used. Therefore, thebumper shell is not only easy to apply in a matter of minutes, but theindividual pieces or complete cover can also be removed and replaced ifdesired for changing the look of the truck or if damaged. This is notpossible with current alternatives.

In order to create a “solid feel” and “dampened sound” rather than ahollow “plasticky” sound and feel inherent with plastic covers, the backside of the present bumper shell's inner surface 58 is coated with asoft elastomer layer 62, such as polyurethane (TPU) or Latex. The softcoating can be relatively smooth or “ribbed” (see FIGS. 9E, 12C, 12E),depending on the amount of gap to be filled. This coating creates a softinterface that dampens sound, overcomes minor surface differences, andprovides a direct load path to create a solid/supported feel that thecustomer will consider higher quality. This soft elastomer is typicallyapplied with a coarse paint brush or flexible applicator.

A preferred method is to form a ribbed pattern in the coating layer's(62) bumper-engaging interface by wiping it with a flexible squeegeethat has a ribbed/toothed edge when the coating has just cured enough tobegin to maintain some shape. When the completed bumper shell is appliedto the bumper, the thin raised ribs bend over/compress where the shellfirst comes in contact with the bumper, thus more able to adjust for gapvariation, which is particularly important if the bumper has beendistorted/damaged. The special coating formulation is developed suchthat when dry, the coating surface remains slightly “tacky”, such thatwhen the bumper shell is applied to the bumper, it will “cling” to it.The additional and novel “clinging” affect provided by the soft coatinggreatly aids in securing the bumper shell to the entire bumper surface.However, as contrasted by an adhesive that is more permanent, the softcoating allows the shell 50,50C to be repositioned and/or removed. Thiselastomeric lining/interface also provides the electro-luminescent panellight source (described in next section) additional protection frommoisture and abrasion. Raised/projected areas 60 (FIG. 7) can also beformed in the bumper shell components and filled with the elastomericmaterial in order to create an in molded “bumperet”, providingadditional low speed impact protection for the truck. (See FIG. 7, whichshows a bumper shell with outwardly “projected” area for added stylingeffect and filled internally for increased impact resistance.)

In addition, when the manufacturing method is vacuum forming, a newtechnique has been developed to eliminate the need for additional trimfixtures, set up fees, and high charge rates for CNC trimming operationsgenerally required for trimming out vacuum formed parts. Thus, thisnovel concept saves significant capital and piece cost expense. Itcomprises forming a raised area, or shoulder, into the tool around theperimeter of the part to be vacuum-formed. A blank flat sheet is heatedto a desired softened temperature suitable for vacuum forming by drawinga vacuum under the blank, to draw it down onto the surface of the tool70. See FIGS. 8A-8C, with FIG. 8B showing a vacuum-formed part 65 on avacuum form tool 70, the vacuum-formed part 65 having a raised perimeter71 (also called “shoulder” or “integral raised guide”) around each ofthe two shells 50 formed.

By way of example, as shown in FIGS. 8B, 8D-8E, the raised perimeter 71acts as a tool guide for guiding around the part (50) amanually-operated cutting tool such as a router or die grinder 72 with arotating cutter/bit 73 and router-attached ridge-engaging guide. In FIG.8D, a bottom of the router is illustrated by the large diameter, therouter guide is illustrated by the intermediate circle, and the routercutter is illustrated by the smaller diameter. The material cutaway bythe router cutter is illustrated by two parallel router-cut linesextending from the cutter downward in FIG. 8D, with the left lineillustrating an edge of the shell 50 cut out by this technique. In theexample, the raised perimeter 71 was 0.4-0.5″ tall, the router cutterwas a ⅛ inch bit, and the illustrated bit collar/guide was 0.665″diameter. The resulting cut line along an edge of the part was 0.395″inboard from the raised perimeter 71. It is noted that the raisedperimeters 71 can include undulations for forming the particularperimeter desired on the shell 50, including for example protruding“bumps” to form the tab 57 or form clearance areas for fasteners on theexisting bumper that the shell must fit around. Persons skilled in thisart will thus understand the many significant advantages using thetechnique set forth above.

It is noted that a variety of different guides or ridge-followers can beused and still be within a scope of the present invention. Theillustrated special guide is a cylindrical bushing or follower used onthe rotating cutting tool or router. It is unusual since it ispositioned to engage a raised ridge located above the cutter (as opposedto known routers where a guide is below the router cutter). Theillustrated router guide is shaped to be maintained in contact with thisraised perimeter shoulder 71 during the trimming operation. Theillustrated guide bushing is fabricated with a specific diameter suchthat the cut for the bumper shell edge is always a specific/constantdistance from the raised perimeter guide. The cutting bit is extendedthrough a hole in the center of the guide, and the guide is attachedsecurely to the rotating cutting tool/router. The trim operation shouldalways occur in a clockwise direction around the part, so the directionof blade rotation helps keep the guide bushing against the shoulder,thus minimizing any tendency for the blade to wander away from itsintended position.

With this method, the need for an additional vacuum fixture iseliminated as is the need for expensive CNC routing of the part, savinga substantial amount of money, especially for lower run quantities. Thetrim guide is trimmed off with the rest of the blank and sent to arecycler. For larger run quantities, CNC routing is advised for trimmingout the part. For even higher volumes, when injection molding is used,the part does not require trimming.

It is contemplated that the outer surface 59 of the present innovativeshells 50 may be decorated in many different ways with an outer surfacecovering 63 (FIG. 9E) and as illustrated by FIGS. 9A-9E, and by usingseveral different methods, such as: A) wrapped with a pre-printedadhesive backed vinyl 63 (FIG. 9E) such as used for decorative vehiclewraps after forming, B) formed using either a material with apre-printed or laminated pattern/color, C) in-mold decorated byinserting a printed film or panel in an injection mold and injecting theshell material on the back surface of the film, D) using thehydrographic process of dipping the formed part into a vat of waterwhere the graphic image to be transferred is floated on the surface.

A preferred and novel method for low volume applications where a backlitimage/logo is desired on the bumper shell is the wrapped vinyl method ona shell 50 made using a clear bumper shell material. The window areawhere the backlighting is desired can either be pre-cut into the filmbefore application to the shell and held in place with transfer tapeuntil application, or cut out of the film after application and removedfrom the film in the region to be backlit when the design shapes aresimple, such as circular or rectangular.

Images/logos for backlighting can be achieved using several methods. Forexample, they can be made by printing (or other indicia 66, see FIG. 11)on translucent colored vinyl and applied to the exposed surface of thebumper shell over the cut out region (i.e. in a “window” area 67). (SeeFIG. 11.) Typically, the image sticker is oversized such that there isapproximately ⅛ inch of overlap with the cut out area to allow forplacement variation and potential material shrinkage differences.Alternatively, the image may also be reverse printed and applied to theinside surface of the bumper shell, so as to expose the printed imagethrough the transparent/clear bumper shell where the decorative film hasbeen trimmed away. Some images are created by the cut out shape in thevinyl with a colored translucent film applied on the backside of theshell. Still other possibilities include a standard window shape cutfrom the vinyl and covered by a colored translucent vinyl 63A (FIG. 12E)either on outside (with prescribed overlap, see FIG. 12E) or on thebackside surface of the bumper shell so as to cover the cut out vinylregion. Available commercial or custom stickers (translucent or not, seefor example the “bowtie” Chevy symbol in FIG. 12D) purchased separatelyfrom licensed vendors by the end user can then be placed over the windowarea by the customer, thus allowing complete freedom of image choicewithout the need for individual licensing.

The image area (i.e. window 67) can be then backlit via severalavailable methods, including electro-luminescent (EL) panel/tape 68(FIGS. 12C or 12E) or LED lighting, which have proven to be particularlyeffective while maintaining a minimal total cross-sectional thickness(e.g. <0.125″). In particular, a preferred method for areas directly andclosely covering the hard bumper surface is with ultra-thin EL paneltechnology. These panels are approximately the thickness of a creditcard, so they can be sandwiched between the bumper shell and surface ofthe bumper behind the image to be backlit without the need to modify thebumper or distort the shape of the shell. They are typically held inplace with tape, although other bonding measures can be used. Also,since they are flat, relatively flexible, and do not utilize a bulb,they can flex to the typical gentle curvatures of a bumper and withstandminor impacts without damage. However, they are susceptible to damagefrom moisture, so the elastomeric coating, which is applied to the backside of the bumper shell after the EL panel is installed, helps to sealout moisture and protect the panel from damage.

From the basic new concepts noted above, there are at least four majoradvancements from current available options for truck bumpers. Theseinclude 1) providing a form-fit decorative shell over a stamped/formedbumper (including retrofittable attachment), 2) providing a carrier/lensfor adding lighted effects, 3) providing protection against rockimpingement, small “dings”, and rust, (as well as a method ofretrofittably covering same without large expense), and 4) providing arelatively inexpensive repair to an already damaged bumper.

More specifically in regard to the subject of providing a form-fitdecorative shell over a stamped bumper, the truck bumper shells of thepresent invention will allow the truck owner to overcome the stylingconstraints on the stamped steel bumpers and limitations of alternativesolutions by changing the surface appearance (texture, pattern, color,and shape) of the exposed steel portions through the application ofdecorative films, customized paint, molded-in colorants/patterns,printed patterns, or mold-behind graphics on to the thin (<3 mm) plasticbumper shell. As explained, the bumper shells can be molded to exactlymatch the contours of the existing bumper. However, additional geometricstyling freedom is possible through localized geometric changes to themolding while still being supported by the steel structure of the bumperand not degrading its impact performance as per the basic concept. Anovel concept has been developed for attaching the shell to the bumperby tucking the flanges under the existing trim pieces and coating thebackside of the bumper shell with a soft and tacky coating, such that it“clings” to the bumper surface and/or by adhesive foam tape. Throughthese means, no modification of the bumper is required. The bumpershells can be easily applied (and removed), if desired, without damagingthe bumper cover or underlying bumper, thus maintaining a pristinebumper underneath.

Examples of the decorative opportunities for restyling the truck areshown in FIGS. 9A-9D. FIG. 9E illustrates one laminar arrangementforming the shell 50. In FIG. 9E, the decorative layer is the left outerlayer, while the intermediate middle layer is a transparent polymericshell, and the innermost layer on the right side is a layer ofsoft/tacky material that adheringly clings to the metal bumper beam'ssurface. The tacky material both fills minor bumps and defects in thebumper beam's surface, and also absorbs small shocks and impactsdirected against the shell 50 by road stones and the like. It iscontemplated that the soft/tacky material can be applied with a trowelto form a plurality of parallel ridges that assist in filling in surfacedefects and in forming an impact-absorbing structure on the bumper beam.

In regard to providing a carrier/lens for adding lighted effects, thetruck bumper shells can be molded from a transparent polymeric material,such as PET-G, Acrylic, or Polycarbonate using either the vacuum formingor injection molding process to give the shell its shape and thickness.See FIGS. 12A-12B and the related cross section FIG. 12C, and also seeFIG. 12D and the related cross section FIG. 12E. Since the bumper shellis mainly designed to fit snuggly over the existing bumper, it issignificant that a durable lighting technology has been identified thatis thin enough to be “sandwiched” between the bumper shell and the rigidsteel bumper surface without distorting the plastic shell or requiringmodification of the steel bumper. Existing known bumper lightingtechnologies typically use either incandescent bulbs or LEDs (see FIG.10). Because of the depth requirement of each of these technologies(i.e. FIG. 10), they each either require a raised/projected surface tobe placed behind or for a depression or hole to be made on the bumper.

Contrastingly, the present invention applies a technology calledelectro-luminescence (see FIGS. 12C and 12E), which is essentiallycreating light by applying a charge (current) with electrodes to a filmconstructed of light emitting phosphor materials and laminated with aprotective film. These electro-luminescent (EL) films come in the formof thin tapes or panels that are typically only 0.02 inch thick. The ELpanels are flexible enough to form around gentle 3D contours, such asthose found in typical stamped truck bumper surfaces (which cannot beaccomplished without great effort with the alternative technologies). Byselecting particular colors and lighting arrangements, words or phrasescan be made to stand out, especially when viewed at dusk or night. SeeFIG. 11 where the word “COOL” is luminated and made to stand out fromthe word “ECOOLOGICIAL”. Also, see FIGS. 12A-12B, where a duck headprofile is made to stand out when lit (FIG. 12B). FIG. 12C illustratesthe arrangement of layers, with the outermost layer on the leftproviding background printed indicia, a first intermediate layer (nextto the outermost layer) being a transparent shell material, a secondintermediate layer (to the right of the other intermediate layer) beingthe EL tape/film, and the right innermost layer being the soft/tackylayer discussed above. FIG. 12D illustrates the opening defining a“bowtie” Chevy symbol (trademark of General Motors), with the outmostlayer having a center area that lights up at a first brightness and aperimeter that is thinner and that lights up with an increasedbrightness over the center area. It is noted that there are an infinitenumber of variations that can be done, using a combination of windowshapes, translucent films applied over the window, brightly-litperimeters, and the like. It is conceived that custom stickers can beprinted on and applied to the “flat” areas on the shell, such as therectangular area illustrated in FIGS. 12D-12E.

Notably, most state highway laws require that rearward facing lights onthe vehicle be diffused and under a particular illumination (candle)power. Since the generated light of the EL panel is evenly diffusedacross the surface of the panel, it does not create “hot spots” of lightbehind the image to be backlit like a bulb or LED, so they meet thisrequirement without the addition of a diffusing lens. Still further, thelight-passing window can form a pattern not unlike a rear light (seeFIG. 13).

The EL panel noted above is typically adhered to the backside of thebumper shell by taping (or other bonding means) around the perimeter inthe area where the backlighting is desired, such as where a printedvinyl film or other semi-transparent image will be placed/created on thebumper shell. The size of the EL panel can be pre-specified from themanufacturer to fit the desired backlit area or trimmed (requiringre-sealing of the cut edges with protective tape) to the desiredshape/size.

By using the present approach with EL panel, images of almost any kind,such as company logos, licensed logos from others, words/messages, etc.can be either printed on vinyl film and applied to the outside surfaceof the bumper shell or airbrushed directly on to the bumper shell, thusmaking a very impressive backlit mobile advertising space. In most casesthe EL panel will have a white light emitted with the color of the imagecoming from what is used on the vinyl sticker to create the image.However, EL panels that emit colors other than white may also be used.In some states, the colors of light on the rear of the vehicle arelimited to red, amber, or white.

The EL panel is charged through a connection to the tail lamp wiring ofthe vehicle. This can be done in many different ways, depending on thedesire of the truck owner. For instance, it can be tied in to therunning lamps, so they illuminate when the headlights or parking lightsare turned on. They can also be tied in with the blinkers or stop lamps,illuminating when either of those conditions occurs. The wires can beconnected by splicing in along the OEM wire harness to the tail lamps orconnected to the trailer light receptacle. In each case, a smalltransformer is required to establish the correct voltage and amperage tothe EL panel and to convert the current from DC to AC.

Once the image is applied to the transparent bumper shell, the rest ofthe bumper shell is either covered with a decorative film, with acut-out for the image or painted after masking the image. If usingdecorative film, the cut-out for the back-lit image can either be asimple perimeter, such as a square, rectangle, circle, or oval aroundthe image or the cut-out can be CNC printed/cut out of the decorativefilm to intermingle with the logo, such as the background betweenletters, etc. In this case, the film is positioned in the printer withspecific datum points, the printed vinyl logo/image can be placed incorrect position on the backside of the decorative film, and then thefilm plus logo is applied in correct position according to the datums onthe bumper shell. Another method is to apply the logo/image to the shellfirst, over the backlit region, and then applying the decorative film byfirst carefully positioning the logo cut-out over the logo and smoothingout the film from the center of the logo to the perimeter of the bumpershell. Still another method is to cut out the wrapped film on the bumpershell in the desired shape/size of window, then carefully place the logoimage “sticker” over the cut out area with approximately ⅛ inch overlapat the edges to account for placement variation and thermal growtheffects. FIG. 12A shows an example of a backlit bumper shell notilluminated, and FIG. 12B shows it illuminated.

It is believed that this additional illumination of the rear of thetruck can provide additional visible warning to vehicles coming up frombehind for increased safety, especially at night or in bad weatherconditions.

Although it is feasible to backlight a directly-applied decorative filmto the bumper, this is not preferred since a thickness of the panel, andthe wire route would visibly distort the film and would not be as wellprotected from damage.

In another situation, where raised/projected areas of the bumper shellare desired, there is room to add LED lights behind the projected areaand backfilled/potted with elastomer (similar to the bumperet) foranother lighted look. These lights can be tied in to light at the sameor different time as the EL panel, such as for blinkers or additionalstop lamps (see FIG. 13).

The present innovation also provides protection against rockimpingement, small “dings”, and rust. It does so much like protectivecovers are used on such things as mobile phones and other electronicdevices to provide the expensive device additional protection fromscratches, impacts, moisture, etc. The illustrated present bumper shellsare designed to protect a new bumper to help maintain it in pristinecondition. Truck bumpers are very expensive to replace, costing between$500-$1,200 for OEM replacement parts. Steel is especially susceptibleto rust and bumpers are subjected to many harsh environments, such assnow, road salt, debris, etc. The chrome or paint covering of the bumperis meant to protect the steel from rusting, but these protectivecoatings are oftentimes compromised/breached by rock impingement, smallimpacts, or scratches. When these coatings are breached, rust forms veryquickly, not only rapidly degrading the look of the truck, but overtime, also compromising the integrity of the bumper itself (see FIG.14).

The bumper shells, including the soft elastomer interface and somesystems including additional raised areas filled with elastomericmaterial can provide substantial protection against common damagingevents such as rock impingement, scratches, and low speed impacts,prolonging the life span of the bumper in its pristine condition.Decorative films directly applied to the bumper provide some protectionfor very minor impacts, like light rock impingement, but issignificantly lower protection than that provided by the bumper shell,due to its thicker substrate and elastomeric interface. In addition,directly applied wrap films cannot cover dents, punctures, orsignificant rust. Aftermarket bumper fascias provide greater protectionthan the films, but are often made of materials that are easily damagedthemselves, such as fiber glass.

Since a new bumper is so expensive, in many cases, a damaged truckbumper is never replaced and the truck owner has had to accept thedegradation of their trucks appearance. However, much like an old housewith peeling paint or damaged exterior can look new again with theapplication of siding, the bumper shells provide a new decorativeoutside surface to a bumper that may have already sustained some minordents, dings, scratches and/or the onset of rust. In addition, in manyinstances, unless severe structural damage and/or distortion of thebumper has already occurred, more substantial dents can be pounded backto near the original shape. A filler material such as used in the bodyrepair industry can then be used to fill in the remaining depressionsand filed/sanded to approximate the original surface. Now, a set ofbumper shells can be applied to the damaged bumper in the same manner asexplained previously for a new bumper. If the trim pieces have beendamaged, they must be replaced. Although, the original surface willnever look new again, when installation of the bumper shells iscompleted, the bumper will have a great new look as shown in FIG. 15.

Unlike directly applied decorative film, the bumper shell of the presentinnovation will cover any remaining imperfections in the repair job andwill serve to help protect the repaired bumper from new damage. (SeeFIGS. 14A and 14B illustrating a damaged bumper beam, and FIG. 15 isillustrating a shell covering the damaged beam.) With this new approach,truck owners will not only save some money and have a new customizedlook for their truck, but will also reduce the waste and energyassociated with the disposal of the old bumper and creation of a newone, including the environmentally damaging chroming process. Theapplication of bumper shells has a much lower environmental impact thanfull replacement.

Thus, it is to be understood that variations and modifications can bemade on the aforementioned structure without departing from the conceptsof the present invention, and further it is to be understood that suchconcepts are intended to be covered by the following claims unless theseclaims by their language expressly state otherwise.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:
 1. A method of repaircomprising: attaching a pre-formed polymeric shell to a formed vehiclebumper beam to cover a show surface of the vehicle bumper beam, thepre-formed polymeric shell having a non-planar three-dimensionalinternal surface that generally matches an original undamaged shape ofthe show surface and having sufficient rigidity to maintain a shape ofthe polymeric shell without full contact against the show surface of theformed vehicle bumper beam.
 2. The method of claim 1, wherein the shellincludes an edge flange oriented to fit under and engage existing trimon the bumper beam to retain the shell to the bumper beam.
 3. The methodof claim 1, including a general repair process of pounding out largerdents and filling remaining surface defects with body filler, sanding tonear original shape, and wherein the step of attaching includesattaching the shell to cover the repaired surface with the pre-formedshell.
 4. The method of claim 1, wherein the inner surface of the shellis coated with a thin layer of low durometer elastomer that provides asoft, anti-abrasion, vibration dampening, impact-protecting, andsound-deadening interface between the shell and the bumper beam.
 5. Themethod of claim 1, including a sound-deadening interface applied to theinner surface and formulated to be tacky, thus enhancing the attachmentto the bumper beam by clinging to the surface of the bumper beam.
 6. Themethod of claim 1, wherein the step of attaching includes positioningthe shell to at least partially cover an end surface, top surface, andface surface of the vehicle bumper beam.
 7. The method of claim 1,wherein the shell has wall thickness of less than 3 mm.
 8. The method ofclaim 1, including providing a sheet, and vacuum forming the sheet intothe shape of shell.
 9. The method of claim 8, including forming apreform that includes the shell and includes an integral raisedperimeter tool guide extending around the shell.
 10. The method of claim9, including trimming the perform using a trimming tool by moving thetrimming tool along the raised perimeter tool guide to trim away excessmaterial from the shell.
 11. The method of claim 1, wherein thenon-planar three-dimensional internal surface includes three surfacesthat intersect to define a concavity matching an end of the vehiclebumper beam.
 12. A method of trimming a shell component comprising:using a vacuum-forming tool to form a vacuum-molded component thatincludes a shell and a raised tool guide extending around a perimeter ofthe shell, the raised tool guide being at a specific distance from adesired trim edge of the shell; and cutting the shell from the componentusing a cutting tool that slideably engages the raised tool guide as thecutting tool is moved around the shell.
 13. The method of claim 12,wherein the cutting tool includes a rotating cutter and a followermember slidably engaging the raised shoulder that positions the rotatingcutter to cut the vacuum-molded component at a known distance from theraised tool guide.
 14. A method of customizing a bumper on a vehiclecomprising: providing a vehicle bumper beam with a convex outer surface;vacuum-forming a molded component from a sheet of constant thicknessmaterial to form a shell having walls of similar thickness but with somestretched wall thicknesses and having a shaped inner surface matching aportion of the convex outer surface; aesthetically treating an outersurface of the shell to form an aesthetic outer surface; and attachingthe molded component to the vehicle bumper beam with the aesthetic outersurface covering a juxtaposed mating portion of the convex outer surfaceof the vehicle bumper beam, to thus give the vehicle a new customizedbumper appearance.
 15. The method of claim 14, including trimming alongan integrally formed raised tool guide in the molded component prior tothe step of attaching.
 16. The method of claim 14, including cutting alight-passing opening and placing a light source near the opening toilluminate the opening.
 17. The method of claim 14, wherein the constantthickness is less than 3 mm.
 18. A method of repair comprising: forminga sheet of constant thickness into a three-dimensionallyconcavely-shaped shell with inner surface replicating a mating showsurface of a vehicle component and with an outer surface aestheticallytreated to provide a customized appearance different than the matingshow surface of the vehicle component; and attaching the shell to thevehicle component to thus cover the mating show surface of the vehiclecomponent.